ID 3.4.23.42 DE thermopsin. CA Specificity similar to pepsin A, prefers bulky hydrophobic side-chains on CA either side of the scissible bond. CC -!- Isolated from cells and culture medium of the thermophilic archae CC Sulfolobus acidocaldarius, optimum digestion at pH 2 and 90 degrees CC Celsius, inhibited by pepstatin. CC -!- Another thermostable bacterial endopeptidase has been isolated from CC Bacillus sp., but this is not inhibited by pepstatin. CC -!- Belongs to peptidase family A5. CC -!- Formerly EC 3.4.99.43. DR P17118, THPS_SULAC ; //